A user group consisting of 10 principal investigators and their research staff at the Boston Biomedical Research Institute is requesting a Radiance Plus Confocal Microscope from Bio-Rad Laboratories. These investigators are conducting a diversity of research projects including: structure function relationships of various proteins in smooth muscle, the determination of signal transduction pathways in intact cells, the interaction of molecular motors with intracellular organelles, the study of non-conventional myosin isoforms, calcium signaling in cardiac muscle cells and the dynamics of beta-amyloid in living cells. The requested instrument will be used for high resolution localization of proteins in cells, quantitative image analysis, colocalization analysis with high spatial accuracy, confirmation of uniform cellular loading of peptides and oligonucleotides into multicellular tissues and cellular fluorescence resonance energy transfer. None of these applications can be satisfied by a standard fluorescence microscope. Due to relocation of the Institute in January 2000, into larger quarters, an existing confocal, which has allowed the collection of preliminary data, will no longer be available and its replacement is urgently needed. The requested instrument will be housed in the Institute's core facility and will be supervised by Dr. Kathleen Morgan, the Director of the Institute and a Senior Scientist; Ms. Cynthia Gallant will be the designated operator; Mr. Gary Henry will be responsible for computer related issues, including image handling, image transfer and computer repair. It is anticipated that research projects at BBRI will almost fully occupy the available instrument time; however, scientists from other research institutions will also be given access on an availability basis, giving preference to NIH funded investigators.